INVESTIGADORES
SOMOZA Gustavo Manuel
congresos y reuniones científicas
Título:
11-ketotestosterone in Pejerrey (Odontesthes bonariensis)
Autor/es:
BLASCO, M.; VIZZIANO, D.; SOMOZA, G.M.
Lugar:
Buenos Aires
Reunión:
Congreso; VII Jornadas Multidisciplinarias de la Sociedad Argentina de Biolog¨ªa.; 2005
Institución organizadora:
Sociedad Argentina de Biolog¨ªa
Resumen:
11-ket0testosterone in pejerrey (Odontesthes bonariensis) Blasco, M1., Vizziano, D2., Somoza G1. 1IIB-INTECH.Chascom¨²s, Argentina2Facultad de Ciencias. Montevideo, Uruguay. e-mail:  mblasco@intech.gov.ar   11-oxo-androgens are well recognized as one of the main effectors of male differentiation in teleost fish and their synthesis involves the 11-¦Â-hydroxylase (P45011B) enzymatic activity. The effect of 11-oxo-androgens in the induction of male phenotype in monosex genetic females is well known. In general, studies on the role of androgens during male sex differentiation are focused on the expression P45011B around the differentiating period. However, there are scarce available data on the capacity of young testes to produce androgens before, during or just after male gonad differentiation. We hypothezised that in pejerrey (a species with a strong temperature sex determination/differentiation, TSD) androgens play a major role during the critical period of determination/differentiation. Two complementary methodologies were developed in order to determine whether the P45011B is expressed and is active in immature pejerrey testes, and to identify the major androgens produced at early stages of gametogenesis. First we cloned and sequenced  a partial fragment of mRNA of P45011B (360 bp) and then, by using biochemical techniques we found that 11-hydroxylase is yet active in  immature (only spermatogonias) fish. In fact, immature testes were able to convert androstenedione and 17¦Á-hydroxyprogesterone into 11-oxygenated derivatives. The main androgen synthesized at this stage was the 11-ketotestosterone  (identified by TLC, HPLC and acetylation). The next step will include the analysis of changes in the enzyme expression and in androgen synthesis by gonads of a cohort of  all male pejerrey during TSD.   Supported by ANPCT (PICT 01-12168) and Proyecto PDT-FPR/F/BI/42/09 (Uruguay).